Bookbinding apparatus

ABSTRACT

In a bookbinding apparatus ( 1 ) comprising an adhesive tank ( 23 ) for retaining therein an adhesive melted by heat, a roller ( 24 ) ratatably supported with the adhesive tank so as to dip a lower portion thereof in the adhesive retained in the adhesive tank, for applying the adhesive to a sheet stack along a lateral edge thereof, and a holding unit ( 18 ) capable of holding the sheet stack, an adhesive tank carrier ( 76, 78 ), the movably constituted adhesive tank ( 23 ) and the roller ( 24 ) are disposed at a stand-by position located outside a longitudinal end face of the sheet stack held by the holding unit ( 18 ) in a stand-by stage so that the adhesive tank is contactlessly heated to melt the adhesive, and are moved together from the stand-by position in a longitudinal direction of the sheet stack substantially through an entire area under a back face thereof in a bookbinding stage.

TECHNICAL FIELD

The present invention relates to a compact and simple bookbindingapparatus to be used in an office, school, home, etc., which applies ahot-melt adhesive in a melted state to a lateral face of a sheet stackcorresponding to a back of a book.

BACKGROUND ART

Up until now, small bookbinding apparatuses for binding a book in asimple manner by applying an adhesive to a sheet stack have beenpopularly used in an office, school, home, etc. Most of such bookbindingapparatuses require a cover specifically designed for the apparatus,provided with a hot-melt adhesive applied in advance to an inner face ofits spine. A sheet stack enclosed in such cover is set in thebookbinding apparatus, and a heater of the apparatus melts the adhesiveprovided inside the cover, thereby bonding the sheet stack and the covertogether.

However, since a specifically designed cover having a predeterminedspine width is used in this type of bookbinding apparatus, a thicknessof the sheet stack to be bound does not always fit the spine width ofthe cover. In such a case a gap is produced between the cover and anuppermost page of the sheet stack, thereby degrading the finish of thebook. Besides, this type of bookbinding apparatus cannot be used for padbinding, which is a method of binding a paper pad coated with anadhesive without enclosing in a cover.

Accordingly, in order to bind a cover in accordance with a thickness ofa sheet stack, or to perform the pad binding, a bookbinding apparatusthat applies a melted adhesive to an end face of a paper pad with aroller and solidifies the adhesive on a flat plate has come to be used.As an example of such type of bookbinding apparatus, Japanese unexaminedpatent publication No. H09-156249 discloses a bookbinding apparatus thatapplies an adhesive to a lower face of a sheet stack by conveying thesheet stack held by a paper holder so as to pass over a coating roller.

However, in this bookbinding apparatus, since the sheet stack moves backand forth over the roller together with the paper holder, in alongitudinal direction along the back of the sheet stack, the apparatushas to be at least wider than a double of the length of the sheet stack;therefore it is difficult to make the apparatus smaller in size. On theother hand, some bookbinding apparatuses are designed such that thesheet stack moves back and forth in a widthwise direction (i.e.thicknesswise direction) on a roller longer than a length of the sheetstack, to apply an adhesive to the back of the sheet stack. Such abookbinding apparatus can be made smaller in widthwise dimension, sincethe sheet stack moves in a widthwise direction (thicknesswise direction)thereof.

However, these types of bookbinding apparatus are generally providedwith an adhesive tank having a large capacity, to replenish the adhesiveless frequently. Especially in case of a bookbinding apparatus thatmoves a sheet stack in a widthwise direction, since the roller has to besufficiently long, the adhesive tank for retaining the adhesive to beapplied to the sheet stack with the roller naturally has to be long, andhence has a large capacity. And in case where the adhesive tank islarge, it takes a longer time in melting the adhesive retained therein,and therefore a start-up period is prolonged, before entering a stand-bystate where the apparatus becomes ready to operate. Besides, a largeramount of adhesive volatilizes from the adhesive tank, resulting inincrease of smell of resin or rubber contained in the adhesive melted bya high temperature.

Accordingly, it is an object of the present invention to provide asmall-sized bookbinding apparatus that can quickly start up to enter astand-by state.

DISCLOSURE OF THE INVENTION

With an object to solve the foregoing technical problem, the presentinvention provides a bookbinding apparatus constituted as under.

A first aspect of the present invention provides a bookbinding apparatuscomprising a movable adhesive tank for retaining therein an adhesivemelted by heat; a roller ratatably supported with the adhesive tank soas to dip a lower portion thereof in the adhesive retained in theadhesive tank, for applying the adhesive to a sheet stack along alateral edge thereof; a holding unit capable of holding the sheet stack;an adhesive tank carrier for disposing the adhesive tank and the rollerat a stand-by position located outside a longitudinal end face of thesheet stack held by the holding unit in a stand-by stage, and moving theadhesive tank and the roller together from the stand-by position in alongitudinal direction of the sheet stack substantially through anentire area under a back face thereof in a bookbinding stage; and anon-contact heater for contactlessly heating the adhesive tank disposedat the stand-by position to melt the adhesive.

In the first aspect, the bookbinding apparatus is a type that appliesthe hot-melted adhesive to the sheet stack for binding. An adhesive tankin which the adhesive is to be retained is movable, and the roller isprovided with the adhesive tank, so that the adhesive is applied to thesheet stack via the roller. The adhesive tank and the roller aredisposed at the stand-by position separated from the lower end face ofthe sheet stack to be coated in the stand-by stage, and are moved alonga longitudinal direction of the sheet stack by an adhesive tank carrierin a bookbinding stage. The adhesive retained in the adhesive tank isheated by the non-contact heater, thus to be melted. The non-contactheater contactlessly heats the member contacting the adhesive such asthe adhesive tank and the roller, so that the adhesive is heated thoughheat transfer. For example, a burner or an induction heater may becited.

According to the bookbinding apparatus of the first aspect, since theadhesive tank can be contactlessly heated in the stand-by stage, theadhesive tank can be easily made movable, and since the adhesive tankmoves during an application of the adhesive, the bookbinding apparatuscan be made smaller in width. Also, since the adhesive tank moves in thelongitudinal direction of the sheet stack, the roller can be madeshorter, and therefore a capacity of the adhesive tank can be reduced.Consequently, diffusion of the smell of the adhesive from the adhesivetank can be suppressed.

A second aspect of the present invention provides the bookbindingapparatus according to the first aspect, wherein the non-contact heateris provided with an electromagnetic induction heating coil; and theadhesive tank is constituted of a material containing a ferromagneticmaterial.

The bookbinding apparatus according to the second aspect permits heatingthe adhesive without directly contacting the adhesive tank, therebymaking it easier to design a carrying mechanism of the adhesive tank.Also, since heat control can be easily performed by adjusting a currentto be supplied to the coil, a temperature of the adhesive can be easilycontrolled. Further, because of high heat exchanging efficiency of aninduction heating coil, power consumption can be saved and the adhesivecan be quickly heated.

A third aspect of the present invention provides the bookbindingapparatus according to the second aspect, wherein the non-contact heateris immovably placed at a stand-by position.

According to the bookbinding apparatus of the third aspect, the adhesivetank alone is moved while the non-contact heater stays at the fixedposition; therefore wiring for the non-contact heater can be easilyarranged. Here, even though the adhesive tank is not heated while theadhesive tank is moving, it does not create any problem for thebookbinding operation, because it is only when applying the adhesive tothe sheet stack in a bookbinding stage that the adhesive tank moves, andsuch time is negligibly short.

A fourth aspect of the present invention provides the bookbindingapparatus according to the third aspect, wherein the adhesive tank isprovided with a container-shaped main body of a non-ferromagneticmaterial for retaining therein the adhesive and a ferromagnetic heatingportion located on an outer surface of the main body; and thenon-contact heater is located so as to confront the heating portion ofthe adhesive tank placed at the stand-by position.

In the bookbinding apparatus according to the fourth aspect, the mainbody of the adhesive tank, which is indirect contact with the adhesiveretained therein, is not directly heated by the coil. Therefore theadhesive can be prevented from being scorched because of overheating atan interface between the adhesive and the adhesive tank.

A fifth aspect of the present invention provides the bookbindingapparatus according to one of the second to fourth aspects, wherein theroller is constituted of a non-ferromagnetic material.

According to the bookbinding apparatus of the fifth aspect, since theroller which makes a direct contact with the adhesive is not directlyheated by the non-contact heater, the adhesive can be prevented frombeing scorched at a contact area with the roller.

A sixth aspect of the present invention provides the bookbindingapparatus according to the first aspect, wherein the adhesive tank isprovided with an inclined bottom wall in an adhesive retaining region ofa container-shaped main body of the adhesive tank to retain the adhesivetherein, for providing a deeper portion corresponding to a position ofthe roller.

According to the bookbinding apparatus of the sixth aspect, forming thedeeper portion on the bottom wall of the adhesive tank corresponding tothe position of the roller facilitates the adhesive to gather close tothe roller so that the roller can be sufficiently dipped in theadhesive. Therefore, even though the adhesive in the adhesive tank hasbeen consumed, the roller can still have a sufficient contact area withthe adhesive.

A seventh aspect of the present invention provides the bookbindingapparatus according to the first aspect, wherein the adhesive tank isprovided with a fin for promoting melting of the adhesive, erected on abottom wall in the adhesive retaining region of the container-shapedmain body of the adhesive tank to retain the adhesive therein.

According to the bookbinding apparatus of the seventh aspect, providingthe fin increases the contact area between the adhesive and the adhesivetank, so that heat is applied to the adhesive via a more extensive area.Consequently, the adhesive can be melted more quickly.

An eighth aspect of the present invention provides the bookbindingapparatus according to one of the first to third aspects, furthercomprising an adhesive supply unit installed opposite to the stand-byposition of the adhesive tank across the sheet stack, including astoring section for storing therein adhesive pellets to be transformedinto the melted adhesive retained in the adhesive tank, a pellet supplypath downwardly extending from a bottom portion of the storing section,and a pellet outlet through which the adhesive pellets transferredthrough the pellet supply path are discharged;

-   -   and an adhesive supply control unit for controlling a supplying        timing of the adhesive pellets from the adhesive supply unit,        such that a predetermined amount of adhesive pellets is        discharged from the pellet outlet to the adhesive tank at a time        that the adhesive tank has reached a position where the adhesive        tank can receive the adhesive pellets discharged from the pellet        outlet, so that the adhesive pellets supplied into the adhesive        tank are melted.

According to the bookbinding apparatus of the eighth aspect, since apellet type adhesive is employed and the gravity is utilized to supplythe pellets through the supply path, a carrying mechanism is notrequired and therefore the adhesive supply unit can be constituted in asmall scale. Also diffusion of smell due to melting the adhesive can beprevented. Further, since the adhesive is supplied when the adhesivetank has moved, the adhesive supply unit can be installed separatelyfrom the stand-by position, which is also a heating position, of theadhesive tank. Therefore, the respective units in the entirety of thebookbinding apparatus do not interfere with one another, and there is nolikelihood that the adhesive pellets inside the adhesive supply unit aresoftened by the adhesive tank heated to a high temperature.Consequently, the bookbinding apparatus can be made smaller indimensions as a whole.

A ninth aspect of the present invention provides the bookbindingapparatus according to the eighth aspect, further comprising a leveldetection unit for detecting a surface level of the adhesive retained inthe adhesive tank; wherein the adhesive supply control unit supplies theadhesive pellets until the adhesive surface exceeds a reference level,when the adhesive surface level has been detected to be lower than thereference level by the level detection unit.

According to the bookbinding apparatus of the ninth aspect, since theadhesive is supplied at the time when a surface level of the adhesiveretained in the adhesive tank has dropped because of consumption, anamount of the adhesive retained in the adhesive tank can be maintainedat a constant level.

A tenth aspect of the present invention provides the bookbindingapparatus according to the eighth aspect, further comprising twoopenable partition plates disposed inside the supply path with apredetermined interval therebetween, so that a predetermined amount ofadhesive pellets are stored between the partition plates; wherein theadhesive supply control unit open or close the two partition platesindependently.

According to the bookbinding apparatus of the tenth aspect, the adhesivesupply unit is provided with two partition plates disposed inside thesupply path with an interval therebetween, so that the supply path canbe opened or closed by manipulating the partition plates. In a regionbetween the two partition plates a certain amount of adhesive pelletscan be stored. Since the two partition plates can be independentlyopened or closed, a determined amount of adhesive can be supplied simplyby discharging the adhesive pellets stored between the two partitionplates.

An eleventh aspect of the present invention provides the bookbindingapparatus according to the tenth aspect, wherein each of the twopartition plates is of a disk shape with an opening, and are fixed by ashaft disposed substantially parallel to the supply path such that arotation phase of the opening of the respective partition plates isdifferent from each other; and the adhesive supply control unit drivesthe shaft to rotate such that only one of the partition plates permits acommunication through the supply path.

According to the bookbinding apparatus of the eleventh aspect, two disksprovided with an opening such as a partial cutaway portion or a throughhole, disposed in a mutually different rotation phase, are rotated by asingle driving device, such that each partition plate can independentlyprovide a path though the supply path. Therefore, a constitution of theadhesive supply unit can be simplified.

A twelfth aspect of the present invention provides an adhesive pellet ofa substantially spherical shape, to be used with the adhesive supplyunit usable with the bookbinding apparatus according to one of theeighth to eleventh aspects.

A thirteenth aspect of the present invention provides the bookbindingapparatus according to one of the first, second, third, fourth andeighth aspects, further comprising a binding mode selection unit forselecting a bookbinding mode according to a signal identifying whether acase binding mode of binding a sheet stack with a cover or a pad bindingmode of binding a paper pad without a cover; and a rotation control unitfor switching a roller controlling mode according to a bookbinding modeselected by the bookbinding mode selection unit.

The bookbinding apparatus according to the thirteenth aspect permitsadjusting an amount of the adhesive to be applied when binding a sheetstack, according to whether or not a book is to be bound with a cover.More specifically, in case of case binding with a cover, the cover andthe sheet stack have to be bonded, while in case of pad binding withouta cover, only the paper sheets held by the holding unit have to bemutually bonded; therefore a different amount of adhesive is required.According to the bookbinding apparatus of this aspect, by adjusting anadhesive amount to be applied, according to whether or not the book isto be bound with a cover, a finish of the book can be upgraded.

A fourteenth aspect of the present invention provides the bookbindingapparatus according to the thirteenth aspect, wherein the adhesive tankcarrier serves to move the adhesive tank and the roller back and forthin a longitudinal direction of the sheet stack; and the rotation controlunit rotates the roller in a forward direction with respect to a movingdirection thereof, during both of the forward and backward travels ofthe adhesive tank, when a pad binding mode in which a cover is notprovided to the sheet stack is selected by the bookbinding modeselection unit.

According to the bookbinding apparatus of the fourteenth aspect,excessive application of the adhesive at a finishing point in a padbinding mode can be prevented by a simple control of the rollerrotation.

A fifteenth aspect of the present invention provides the bookbindingapparatus according to the thirteenth aspect, wherein the adhesive tankcarrier serves to move the adhesive tank and the roller back and forthin a longitudinal direction of the sheet stack; and the rotation controlunit rotates the roller in a different direction according to a movingdirection thereof.

According to the bookbinding apparatus of the fifteenth aspect, since arotating direction of the roller is switched according to a movingdirection thereof, a rotating direction of the roller remains unchangedduring a travel in either direction. Therefore, uneven application ofthe adhesive can be prevented and a better finish can be achieved.

A sixteenth aspect of the present invention provides the bookbindingapparatus according to the fifteenth aspect, further comprising athickness detecting device for detecting a thickness of the sheet stackheld by the holding unit; wherein the rotation control unit stops arotation of the roller during a forward travel of the adhesive tank butrotates the roller in a reverse direction with respect to the movingdirection during a backward travel when a thickness of the sheet stackhas been detected to be equal to or thinner than a reference thickness,while the rotation control unit rotates the roller in a forwarddirection with respect to a moving direction thereof during both of theforward and backward travels of the adhesive tank, when a thickness ofthe sheet stack has been detected to be thicker than the referencethickness, in case where the case binding mode of providing a cover tothe sheet stack is selected by the bookbinding mode selection unit.

In case of the case binding, a finish of a book largely depends on anamount of applied adhesive, because the cover and the sheet stack mayfall apart or the adhesive may be squeezed out of a joint area, unlessan appropriate amount of adhesive is applied. When the sheet stack isthinner than a reference thickness, a smaller amount of adhesive tendsto be applied; therefore the roller is made to rotate so that a largeramount of adhesive can be applied. Specifically, during a forward travelthe roller is stopped so that less adhesive is applied. On the otherhand, during a backward travel the roller is made to rotate in a reversedirection with respect to a moving direction thereof, in order tofinally apply the adhesive to the back of the sheet stack. In otherwords, the roller moves in an opposite direction to a direction normallycaused by the rotation. Such rotation of the roller increases a relativespeed between the sheet stack and a contact surface of the roller,thereby causing the adhesive stuck to the roller surface to be scrapedoff toward the back of the sheet stack, and resultantly a larger amountof adhesive is applied.

By contrast, when a thickness of the sheet stack exceeds a referencethickness, a larger amount of adhesive is often applied; therefore theroller has to rotate so as to prevent an excessive application of theadhesive. Specifically, in order to maintain a same applying condition,the rotating direction is switched so that the roller rotates toward anupstream side with respect to moving direction of the roller during bothforward and backward travels. Such rotation of the roller reduces arelative speed between the sheet stack and a contact surface of theroller, thereby preventing an excessive application of the adhesive.

Consequently, according to the bookbinding apparatus of the sixteenthaspect, an appropriate amount of adhesive can be applied with a simplearrangement by rotating the roller in a different direction according toa moving direction thereof, in the case binding mode.

A seventeenth aspect of the present invention provides the bookbindingapparatus according to the sixteenth aspect, wherein the referencethickness is in a range of 1.8 to 2.2 mm.

An eighteenth aspect of the present invention provides the bookbindingapparatus according to one of the thirteenth to sixteenth aspects,further comprising a position detection unit for detecting a position ofthe adhesive tank, wherein, once the adhesive tank reaches apredetermined position during a backward travel, the rotation controlunit stops the rotation of the roller during the subsequent travel ofthe adhesive tank from the predetermined position to a final edge of thesheet stack.

Referring to the bookbinding apparatus according to the presentinvention, a large amount of adhesive is prone to stick to an endportion of the sheet stack, because the adhesive on the roller surfaceis scraped off by a lateral edge at both ends of the sheet stack.Especially in case of case binding with a cover, an excessive amount ofadhesive stuck to end portion of the sheet stack produces a protrusionof solidified adhesive, resulting in a defective finish of the book.Therefore, it is desirable to prevent deposition of a large amount ofadhesive at both edges of the sheet stack.

For this purpose, the adhesive tank is moved with the roller stopped, inthe proximity of a final edge of the sheet stack. By such arrangement,the adhesive is no longer supplied from the adhesive tank, and theadhesive remaining on the roller surface is spread over in a regionclose to the edge of the sheet stack. Consequently, deposition of anexcessive amount of adhesive in the proximity of a final edge of thesheet stack can be prevented.

Also, a reason that the roller is stopped only in a backward travel inthe foregoing constitution is that surplus adhesive stuck to the endportion in a forward travel can be removed by the roller on its wayback, while surplus adhesive on the end portion in the backward travel(the final end) cannot be thus removed by the roller. Accordingly, theabove constitution permits easily removing the excessive adhesive bychanging an applying condition via the roller.

Consequently, according to the bookbinding apparatus of the eighteenthaspect, by moving the adhesive tank with the roller stopped in theproximity of an edge of the sheet stack, where an excessive amountadhesive is prone to stick, the adhesive is no longer supplied from theadhesive tank, and the adhesive remaining on the roller surface isapplied so as to be spread over. Consequently, deposition of anexcessive amount of adhesive in the proximity of a final edge of thesheet stack can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects and features of the present invention willbecome clear from the following description taken in conjunction withthe preferred embodiments thereof with reference to the accompanyingdrawings, in which:

FIG. 1 is a perspective view showing an outer appearance of abookbinding apparatus according to an embodiment of the presentinvention;

FIG. 2 is a front view showing a part of inner structures of thebookbinding apparatus of FIG. 1;

FIG. 3 is a left side view showing a part of inner structures of thebookbinding apparatus of FIG. 1;

FIG. 4 is a front view showing a layout of units with an applicationunit set at a stand-by position;

FIG. 5 is a left side view showing a layout of units with theapplication unit set at the stand-by position;

FIG. 6 is a fragmentary perspective view showing a constitution of apressing unit;

FIG. 7 is a view for explaining a clamp operating mechanism;

FIG. 8 is a view showing a travel of an adhesive tank;

FIG. 9A is a plan view showing a constitution of an adhesive supplyunit;

FIG. 9B is a right side view showing a constitution of the adhesivesupply unit;

FIGS. 10A, 10B, 10C, 10D, 10E, 10F, 10G, and 10H are schematic views forexplaining an operating process of the adhesive supply unit;

FIG. 11A is a fragmentary left side view showing a layout related to adeodorizing unit;

FIG. 11B is a fragmentary front view showing a layout related to thedeodorizing unit;

FIG. 12A is a plan view showing a constitution of the adhesive tank andthe roller;

FIG. 12B is a cross-sectional view taken along the line A-A of FIG. 12A;

FIG. 13 is a view for explaining a contact position of the roller and asheet stack;

FIG. 14 is a block diagram showing a control system of the bookbindingapparatus according to the embodiment;

FIG. 15 is a flowchart showing a bookbinding process performed by thebookbinding apparatus according to the embodiment;

FIG. 16A is a view showing a descending position of the pressing unit;

FIG. 16B is a view showing a state of setting the sheet stack after thepressing unit is lifted;

FIG. 17 is a view for explaining a reference position for setting acover;

FIG. 18A is an explanatory view showing a rotating direction of theroller during a travel of the adhesive tank in case where a sheet stackis thinner than a reference thickness in a case binding mode;

FIG. 18B is an explanatory view showing a roller rotating direction ofthe roller during a travel of the adhesive tank in case where the sheetstack is thicker than the reference thickness in a case binding mode;

FIGS. 19A and 19B are views for explaining an operation of a pressingforce controlling mechanism of the pressing unit;

FIGS. 20A, 20B, 20C and 20D are views progressively showing a bookdischarging process;

FIG. 21 is a view showing a layout of an operation panel of thebookbinding apparatus of FIG. 1; and

FIG. 22 is a line graph showing a relation between an amount of appliedadhesive and a rotating direction of the roller.

BEST MODE FOR CARRYING OUT THE INVENTION

Before the description of the present invention proceeds, it is to benoted that like parts are designated by like reference numeralsthroughout the accompanying drawings.

FIG. 1 is a perspective view showing an outer appearance of abookbinding apparatus according to an embodiment of the presentinvention. The bookbinding apparatus 1 is a generally box-shapedapparatus, provided with a casing including a front housing 10constituting a front and an upper face of a main body, and a rearhousing 11 constituting a rear and an upper face thereof. The fronthousing 10 and the rear housing 11 are fixed to a frame 28, 29, 41 a and41 b (Ref. FIG. 7) provided inside the main body, as will be describedlater. The rear housing 11 is provided with a rear cover 12 on a rearface thereof, which has an inclined wall for securing an additionalspace for a cover for bookbinding (110 x of FIG. 20A) and a movableplate 46, and for bending the cover 110 x downward to retain temporarily(Ref. FIGS. 20A and 20C).

As an outer structure, the bookbinding apparatus 1 is provided with alower front door 13 openably installed below the front housing 10, anoperating knob 14 for opening or closing a clamp unit 18 which holds asheet stack when in operation, a cover tray 15 for placing thereon acover for bookbinding, and an operating panel 16.

Also, the clamp unit 18 is installed on an upper face of the main body.The clamp unit 18 is constituted of a pair of generally rectangularplates, a fixed clamp 18 a and a movable clamp 18 b, disposed parallelto each other in a perpendicular direction, so as to partly protrudeupwardly through a gap 17 provided on an upper face of the main body. Asalready stated, by manipulating the operating knob 14 the movable clamp18 b is moved so as to vary an interval between the clamps, for fixingor releasing the sheet stack. At an upper end potion of the clamps 18 aand 18 b, sheet stack supporters 19 a and 19 b are detachably attachedrespectively, for preventing a portion of the sheet stack projectingabove the clamp unit 18 from downwardly bending to thereby causemisalignment of the papers, when binding a vertically lengthy sheetstack.

Inside the main body, various units such as an application unit 2, adeodorizing unit 3, a pressing unit 4 and an adhesive supply unit 5 areinstalled, as shown in FIGS. 2, 3 and 8. As shown in FIG. 2, theapplication unit 2 is usually disposed at an outer position from alateral edge of the clamp unit 18, and a portion of the application unit2 is designed to slide along a lower end of the clamp unit 18, asdescribed later.

The deodorizing unit 3 is disposed so as to extend downwardly from aposition above the application unit 2 as shown in FIGS. 2 and 3, foraspiring adhesive vapor that has volatilized from an adhesive tank 23and a roller 24 of the application unit 2, so that a built-in filteradsorbs the vapor.

The pressing unit 4 is disposed under the clamp unit 18 as shown in FIG.3, and is designed to move forward and backward, as well as upward anddownward as described later. When the application unit 2 moves, thepressing unit 4 is lowered so that the application unit 2 can pass underthe clamp unit 18.

FIGS. 4 and 5 are drawings showing a layout of the units with theapplication unit 2 set at a stand-by position. The application unit 2and the clamp unit 18 are both installed on two frames 28 and 29. Thefront frame 28 has a [-shaped cross section, and sustains the fixedclamp 18 a on its vertical portion 28 b, while a horizontal portion 28 aserves as a rail for the adhesive tank 23 to slide thereon. The rearframe 29 also has a [-shaped cross section, and is provided with amoving mechanism for moving the movable clamp 18 b. Also, the rear frame29 sustains a rail shaft 33, which serves as a guide for a travel of theadhesive tank, on its vertical portion 29 b.

The application unit 2 is disposed at an outer position from a lateraledge of the clamp unit 18 and at a lower position from a lower edgethereof. The application unit 2 is provided with an induction coil 20attached to a base plate 20 a, which serves as a heater, so as to heatthe adhesive without contacting with the adhesive tank 23 by inductionheating of a ferromagnetic material, when the adhesive tank is at thestand-by position.

Above the adhesive tank 23, the roller 24 is disposed so as to dip aportion thereof in the melted adhesive. The roller 24 is ratatablysupported by a supporter 25, and is made to rotate by a roller rotatingmotor 21 via a shaft 22.

The adhesive tank 23 is provided with a coupling unit 26 extendingupwardly from an end portion thereof, and a roller 27 attached at an endportion of the coupling unit 26 is engaged with the rail, constituted ofthe horizontal portion 28 a of the front frame 28. Also, a guide member34 is attached at the other end portion of the adhesive tank 23, whichis engaged with the rail shaft 33 provided on the vertical portion 29 bof the rear frame 29. These two engagements permit the adhesive tank 23to slide along the frames 28 and 29, to thereby move under and along theclamp unit 18 attached to the frames 28 and 29.

Now referring to FIG. 7, an operation mechanism of the clamp unit-18will be described. As already mentioned, the fixed clamp 18 a isattached to the front frame 28, and an operation mechanism of themovable clamp 18 b is located on the rear frame 29. The movable clamp 18b can be moved so as to vary an interval from the fixed clamp 18 a, bymanipulating the operating knob 14, for the purpose of holding the sheetstack between the clamps.

When rotating the operation knob 14, a threaded shaft 36, connectedthereto via a shaft of the operating knob 14 and a belt 35, is caused torotate. A rotating force of the threaded shaft 36 is transmitted toanother threaded shaft 37 via a belt 40, thereby interlocking therotation of the both threaded shafts. The threaded shafts 36 and 37 areengaged with a threaded hole 29 s on a back-up plate 29 h to which themovable clamp 18 b is fixed; therefore a rotation of the threaded shafts36 and 37 causes the movable clamp 18 b to move together with theback-up plate 29 h.

Between the fixed clamp 18 a and the movable clamp 18 b, guide shafts 39a and 39 b are provided, so that the movable clamp 18 b is constantlymaintained parallel to the fixed clamp 18 a because of moving along theguide shafts 39 a and 39 b. Meanwhile, the guide shaft 39 a, located onthe left when viewed from a forward direction of the bookbindingapparatus 1, serves as a positioning reference in a longitudinaldirection for the sheet stack as described later, to thereby determine aholding position of the sheet stack in cooperation with the fixed clamp18 a, which serves as a reference in a thicknesswise direction.

The back-up plate 29 h is provided with a detection piece 38 attached atan end portion thereof. The detection piece 38 cooperates with the sheetstack thickness sensor 34 constituted of a photointerrupter, to detectwhether a sheet stack is thinner than a predetermined referencethickness. Specifically, in case where a sheet stack held by the clampunit 18 is thicker than the reference thickness, the detection piece 38does not reach the sheet stack thickness sensor 34 and hence does notinterrupt the sheet stack thickness sensor 34, however when the sheetstack is thinner than the reference thickness the movable clamp 18 bcomes closer to the fixed clamp 18 a, thereby causing the detectionpiece 38 to interrupt the sheet stack thickness sensor 34. Aninformation of a thickness of the sheet stack is used as an index todetermine a rotating direction of the roller 24 when applying theadhesive, as described later.

FIG. 8 is a drawing showing a travel of an adhesive tank. As alreadymentioned, the adhesive tank 23 is designed so as to slide in such astate that the adhesive stuck to a surface of the roller 24 is incontact with a lower end face of the sheet stack 100 held by the clampunit 18. In order to detect a position of the adhesive tank 23, sensors31 a, 31 b and 31 c constituted of a photointerrupter are provided. Inthe bookbinding apparatus 1 according to this embodiment, the sensors 31a, 31 b and 31 c are disposed on a sensor supporting frame 30 fixedbetween a right frame 41 a and left frame 41 b both fixing the frontframe 28 and the rear frame 29. The sensors are respectively defined asa first position sensor 31 a for detecting the adhesive tank 23 at thestand-by position, a third position sensor 31 c for detecting theadhesive tank at a farthest position of the travel, and a secondposition sensor 31 b located in the middle of the other sensors. Thesesensors detect a position of the adhesive tank 23 each time a detectionpiece 32 attached to the adhesive tank 23 interrupts the respectivesensors while the adhesive tank 23 is moving.

Also, as shown by a dotted line 2 x in FIG. 8, the adhesive supply unit5 for replenishing the adhesive tank with the adhesive is installed at aposition corresponding to the farthest travel position of the adhesivetank 23. The adhesive supply unit 5 stores adhesive pellets in a hopper51, to supply a predetermined amount of adhesive in the adhesive tank 23at an appropriate timing.

FIGS. 9A and 9B are drawings showing a constitution of the adhesivesupply unit 5. The adhesive supply unit 5 includes the hopper 51 forstoring therein the adhesive pellets, a downwardly inclined duct 52connected to a lower portion of the hopper 51 and an outlet 56 throughwhich the adhesive is to be supplied to the adhesive tank 23. The duct52 is provided with two partition grooves 57 a and 57 b, and partitionplates 55 are placed in the respective partition grooves 57 a and 57 b.The partition plates 55 are respectively defined as a first partitionplate 55 a which is closer to the hopper 51, and a second partitionplate 55 b which is farther. The first partition plate 55 a and thesecond partition plate 55 b are of a disk shape with a partial cutawayportion, disposed mutually parallel in a shifted rotation phase so thatthe cutaway portions to not overlap, and are fixed to a shaft 54 at acentral portion of the disks. The shaft 54 is connected to a partitionplate driving motor 53, so that the first partition plate 55 a and thesecond partition plate 55 b rotate together when the motor 53 isactivated.

The adhesive supply unit 5 rotates the shaft 54 by a predetermined angleso as to control a rotational position of the first partition plate 55 aand the second partition plate 55 b, such that the adhesive pelletsstored in the hopper 51 is supplied to the adhesive tank 23, in a lot ofa predetermined amount each time.

FIGS. 10A to 10H are schematic drawings for explaining an operatingprocess of the adhesive supply unit. Initially, the two partitionplates, the first partition plate 55 a and the second partition plate 55b, are disposed so as to respectively close an opening of the duct 52,as shown in FIGS. 10A and 10B. Accordingly, the adhesive pellets 105stored in the hopper 51 are located on an upstream side of the firstpartition plate 55 a.

When the first partition plate 55 a and the second partition plate 55 brotate by 90 degrees around the rotation center 54 c in a direction ofthe arrow 200, the situation turns to a state shown in FIGS. 10C and10D. In this state, the cutaway portion of the first partition plate 55a overlaps the opening to provide a path; therefore the adhesive pellets105 move to an intermediate duct 57 as indicated by the arrow 201. Yet,the adhesive pellets cannot move further downstream since the secondpartition plate 55 b is covering the opening, in this state.

When the first partition plate 55 a and the second partition plate 55 brotate by another 90 degrees around the rotation center 54 c in adirection of the arrow 200, the situation turns to a state shown inFIGS. 10E and 10F. In this state, since both of the first partitionplate 55 a and the second partition plate 55 b are covering theopenings, the adhesive pellets exist both in the intermediate duct 57and on an upstream side of the first partition plate 55 a in the duct52. However, the adhesive pellets 105 a in the intermediate duct 57 areisolated by the first partition plate 55 a from the adhesive pellets 105b on an upstream side.

Again, when the first partition plate 55 a and the second partitionplate 55 b rotate by another 90 degrees around the rotation center 54 cin a direction of the arrow 200, the situation turns to a state shown inFIGS. 10G and 10H. In this state, the cutaway portion of the secondpartition plate 55 b overlaps the opening to provide a path, so that theadhesive pellets 105 a in the intermediate duct 57 move toward theoutlet 56 as indicated by the arrow 202. Also, since the first partitionplate 55 a is still covering the opening, the adhesive pellets 105 inthe duct 52 cannot move forward. Therefore, only the adhesive pellets105 a in the intermediate hopper 57 can move to the outlet 56.Consequently, by adjusting a capacity of the intermediate duct 57 so asto match a desired replenishing amount, an appropriate amount ofadhesive pellets can be automatically supplied to the adhesive tank 23.

Now the deodorizing unit 3 will be described. As already mentioned, thedeodorizing unit 3 serves to aspire the adhesive vapor that hasvolatilized from the adhesive tank 23 and the roller 24 of theapplication unit 2, so that a filter adsorbs the vapor. Specifically,the deodorizing unit 3 is constituted of a cylinder provided with asuction port 60 and a discharge port 63, and a filter 61 is located in aduct 64 which constitutes a middle portion of the cylinder as shownFIGS. 11A and 11B. A known filter that can adsorb ingredients of theadhesive may be employed as the filter 61.

A ventilating fan 62 is provided in the proximity of the discharge port63, and is discharging air outwardly through the discharge port 63.Accordingly, air is aspired through the suction port 60, and passesthrough the filter 61 to be discharged through the discharge port 63.The suction port 60 is disposed with the adhesive tank 23 and the roller24, in order to aspire air containing the ingredients of the adhesivethat have volatilized from the adhesive tank 23 and the roller 24. Theair aspired through the suction port 60 flows through a gap 64 aprovided in the duct 64 and passes from a front face of the filter 61 toa rear face thereof, during which the ingredients of the adhesive areadsorbed and removed. The air then reaches another gap 64 b locatedopposite to the gap 64 a across the filter 61, and proceeds to thedischarge port 63 because of a suction force of the ventilating fan 62,to be finally discharged through the discharge port 63. Therefore, thedischarged air only contains a reduced amount of adhesive ingredients,and consequently diffusion of smell due to heating the adhesive can berestrained.

Then a constitution of the adhesive tank 23 and the roller 24 will bedescribed. Since the adhesive tank 23 is designed to heat the adhesivevia the induction coil 20, the adhesive tank 23 has to at leastpartially include a ferromagnetic material. In the adhesive tank 23according to this embodiment, a tray main body 23 a is constituted ofaluminum, which is highly thermoconductive and non-ferromagnetic, and aferromagnetic heating plate 72 is provided at a bottom portion of thetray main body 23 a. Also, a plurality of fins 70 is vertically formedon a bottom portion of an inner face of the tray main body 23 a, toincrease a contact area between the tray main body 23 a and theadhesive. Because of such constitution, when heating the adhesive, heatproduced by the heating plate 72 is conducted to the tray main body 23 amade of aluminum, which is highly thermoconductive, to therebyefficiently heat the adhesive over an extensive area. Consequently,since the adhesive is uniformly heated without directly heating the traymain body 23 a, overheating of a contact area between the adhesive andthe tray main body 23 a, and hence scorching of the adhesive, can beprevented.

Also, the tray main body 23 a is formed in such a shape that aperipheral region is shallower while a central region above which theroller 24 is located is deepest. Such shape facilitates the adhesive togather close to the roller 24 even when the adhesive in the adhesivetank 23 has been consumed, thereby permitting the roller 24 to besufficiently dipped in the adhesive.

Further, the main body 23 a of the adhesive tank 23 is provided with apair of thermocouples 71 a and 71 b, by which a temperature of theadhesive can be measured. Among the pair of thermocouples 71 a and 71 b,one is a temperature detecting thermocouple 71 a for measuring theadhesive temperature at a deep portion of the tray main body 23 a.According to an output from the thermocouple 71 a, power supply to theheating coil 20 is turned on and off so as to maintain an appropriatetemperature for the adhesive being used.

On the other hand, the other thermocouple is a surface level detectingthermocouple 71 b for measuring the adhesive temperature at a shallowportion of the tray main body 23 a. When the adhesive has been consumeda surface level of the adhesive drops lower than a position of thethermocouple 71 b, by which the thermocouple 72 b detects a temperaturelower than a predetermined value, and transmits a signal to such effectto a control unit 76 (Ref. FIG. 14) including a CPU. The control unit,in receipt of the signal, operates the adhesive supply unit 5 to refillthe adhesive.

The roller 24, which is ratatably supported with the adhesive tank 23,includes a main portion 24 c and a concentric flange portion 24 b whichhas a greater diameter than the main portion 24 c as shown in FIGS. 12Aand 12B. Also, a pair of squeegees 69 is disposed on both sides of theroller 24, to scrape off an excess of the adhesive stuck to a surface ofthe roller 24. Here, an amount of the adhesive to be applied by theroller can be controlled by adjusting a gap between a surface of theroller 24 and the squeegee.

Based on such structure, application of the adhesive can be efficientlyperformed by uniformly determining a reference position for a sheetstack through a collaboration of the flanged roller 24 and the fixedclamp 18 a. Now referring to FIG. 13, a reference position of a sheetstack to be determined in the bookbinding apparatus according to thisembodiment will be described. As already stated, the clamp unit 18includes a fixed clamp 18 a disposed on a forward side. Accordingly,when setting a sheet stack, a lower end portion of an inner face of thefixed clamp 18 a can constantly serve as a reference position Rcorresponding to a lateral face on a forward side of the sheet stack.Therefore, the roller 24 which is to apply the adhesive to a back of thesheet stack is disposed such that the flange portion 24 b is located ata forward side of the reference position R by a distance A. Because ofsuch flange portion 24 b included in the roller 24, the adhesive 106 astuck to a surface of the flange portion 24 b is applied to theproximity of a lowermost portion of a front face of the sheet stack 100,in addition to a bottom face 106 thereof. A width of the adhesive to beapplied to a lowermost portion of a front face of the sheet stack 100can be easily adjusted by a height of the flange portion 24 b of theroller 24. Applying the adhesive in this way to a lowermost portion of afront face of the sheet stack can further strengthen the adhesion of thesheet stack and a cover, thereby resulting in a sturdy finish.

Now the pressing unit will be described. FIG. 6 is a fragmentaryperspective view showing a constitution of the pressing unit. Asmentioned above, the pressing unit 4 is constituted such that an entireunit can move upward and downward as indicated by the arrow 211, as wellas forward and backward as indicated by the arrow 212. The pressing unitincludes a fixed plate 43 attached on a base member 48, the cover tray15 located on a forward side of the fixed plate 43, and a movable plate46 located on a rear side of the fixed plate 43.

The fixed plate 43 serves as a base to which a lower face of the sheetstack is butted for alignment when in operation, and is provided with asmoothing finish such as a fluororesin coating on upper surface thereof,to prevent the adhesive from sticking thereto in a pad binding process.Along a front side lateral edge of the fixed plate 43, a block bar 44 isprovided, for cooperating with the movable plate 46 in folding a coverin a bookbinding operation, as will be later described.

A shooter 45 is provided on a forward side of the fixed plate 43, fordischarging a finished book outwardly, as described later. Also, a pairof supporting members 47 is provided on both end portions of the shooter45, for sustaining the cover tray 15. Accordingly, a gap 45 a is formedbetween the fixed plate 43 and the tray cover 15, so that a finishedbook falls to the shooter 45 through the gap 45 a, to be discharged outof the apparatus (Ref. FIG. 20D).

Also, the cover tray 15 is provided with a positioning scale 15 a for acover arranged on to the cover tray 15, to be used for positioning of alarge-sized cover. The positioning scale 15 a is slidably attached tothe cover tray 15 as indicated by the arrow 260, and a size scaleshowing a cover size is marked on the positioning scale 15 a, foradjusting a position of a large-sized cover that protrudes from thecover tray 15.

The movable plate 46 is slidably installed as indicated by the arrow210, so that an interval from the block bar 44 attached to the fixedplate 43 can be adjusted. Specifically, a lateral face 46 a on a frontside of the movable plate 46 and the block bar 44 hold the sheet stacktherebetween and press it, to ensure adhesion of the sheet stack and acover.

Now, operation of the bookbinding apparatus according to this embodimentwill be described hereunder. The operation of the bookbinding apparatus1 is integrally controlled by the control unit 76, and various sensorsfor detecting an operational status and motors for driving thecomponents are incorporated. FIG. 14 is a block diagram showing acontrol system of the bookbinding apparatus according to thisembodiment.

The bookbinding apparatus according to this embodiment includes thefollowing sensors; the sheet stack thickness sensor 34, the first tothird adhesive tank position sensors 31 a to 31 c, the temperaturedetecting thermocouple 71 a, the surface level detecting thermocouple 71b, and further a clamp stop sensor 75 (Ref. FIGS. 19A and 19B), an upperclamp sensor 73 and lower clamp sensor 74 (not shown) to be describedlater. The upper clamp sensor 73 and lower clamp sensor 74 serve fordetecting an uppermost position and a lowermost position of the pressingunit 4 in its vertical movement.

Also, the bookbinding apparatus according to this embodiment includes,as driving sources, the roller rotating motor 21 and the partition platedriving motor 53 which have already been described, and further anadhesive tank driving motor 78, clamp motor 79 for forward and backwardmovement, clamp motor 80 for vertical movement, and a movable platedriving motor 83. The adhesive tank driving motor 78 serves for movingthe adhesive tank 23 of the application unit 2, so that the adhesivetank 23 moves together with the roller and the roller rotating motor 21.The clamp motor 79 for forward and backward movement and the clamp motor80 for vertical movement serve as the driving source for a forward andback movement and an upward and downward movement of the pressing unit 4respectively. The movable plate driving motor 83 is for driving themovable plate 46 of the pressing unit 4.

Further, the bookbinding apparatus according to this embodimentincludes, as an operation unit, the operation panel 16, a ROM 81 and aRAM 82 serving as a storage region and an arithmetic region according toa program on a drive control, and a high-frequency supply source 77which supplies a high-frequency current to the heating coil 20.

The operation panel 16 is provided with switches including a startswitch 161, a stop switch 162, a setting switch 163, and bookbindingmode selection switches 164 a and 164 b, and display screen 165, asshown in FIG. 21. The start switch is for starting a bookbindingoperation in a bookbinding process to be described later, and the stopswitch 162 is for suspending a bookbinding operation halfway or forturning off the power. The setting switch 163 serves for setting variousvalues, and the bookbinding mode selection switches 164 a and 164 b areused for manual input of a distinction of whether a pad binding or acase binding. The pad binding is a bookbinding mode of applying anadhesive to the sheet stack without a cover to bind the sheet stackalone, while the case binding is the bookbinding mode wherein a cover isused, and the sheet stack face to which an adhesive has been applied anda spine of the cover are bonded together. The display screen 165displays various instructions related to a progress of the bookbindingoperation and information for setting various values.

FIG. 15 is a flowchart showing a bookbinding process performed by thebookbinding apparatus according to this embodiment. In the bookbindingapparatus, after the power is first turned on, the heating coil heatsthe adhesive tank, and when the temperature detecting thermocouple 71 adetects that the adhesive has melted and reached a predeterminedtemperature, the roller rotating motor 21 is activated to rotate theroller 24 (stand-by state). Since the bookbinding apparatus 1 accordingto this embodiment has a small-capacity adhesive tank and hence anamount of the adhesive to be melted is small, and since the inductionheater which offers a high thermal efficiency is provided, a time beforereaching the stand-by state can be significantly shortened compared witha conventional apparatus, and volatilization of the adhesive can also besuppressed. Also, since the deodorizing unit 3 adsorbs ingredients ofthe adhesive that have volatilized, diffusion of smell can be prevented.At the stand-by state, the following bookbinding operation is performed.

When starting an operation after turning on the power, an operatorselects the bookbinding mode (step #10). Selection of the bookbindingmode is performed through manipulating the bookbinding mode selectionswitch on the operation panel. A signal of the selected mode input bythe manipulation on the operation panel is output to the control unit 76and temporarily stored in the RAM 82.

The control unit 76 remains in the stand-by state until a switch on theoperation panel 16 is turned on. Once the operator manipulates the startswitch 161 and information to the effect that the start switch has beenturned on is output (step #11), the control unit 76 activates the clampmotor 80 for vertical movement so that the pressing unit 4 is lifted,(step #12). These steps are shown in FIGS. 16A and 16B. As shown in FIG.16A, since the pressing unit 4 is at a lower position in the stand-bystate, a reference position for a lower face of a sheet stack cannot bedetermined for setting a sheet stack 100 in the clamp unit 18;therefore, the pressing unit 4 is lifted so as to define a lower facereference position such that an interval between a lower edge of theclamp unit 18 and the fixed plate 43 becomes a predetermined value (8mm). Then a lower end face of the sheet stack 100 is butted to the fixedplate 43 as shown in FIG. 16B, and the operation knob 14 is rotated tofix the sheet stack in the clamp unit 18 (step #13).

Upon having set the sheet stack 100 in the clamp unit 18, the operatormanipulates the start switch 161 on the operation panel 16 again, toemit a signal to such effect (step #14). Once the switch-on signal isemitted, the control unit 76 drives the clamp motor 80 for verticalmovement so that the pressing unit 4 is lowered, until detected by thelower clamp sensor 73 (step #15), so as to secure a space between theclamp unit 18 and the pressing unit 4, through which the adhesive tank23 can move.

In case where the case binding mode is selected, the apparatustemporarily stops the action when the pressing unit 4 has been lowered.At this stage, the operator sets the cover to be used for the casebinding, on the cover tray 15 (step #17).

The cover setting is performed by placing the cover on the cover tray 15and the movable plate 46 of the pressing unit 4, as stated above. Sincethe bookbinding apparatus according to this embodiment is provided withthe fixed clamp 18 a on a forward side of the clamp unit 18 as alreadymentioned, an edge of the cover can be easily aligned, and positioningcan be performed by matching a forward side lateral edge of the coverwith the scale marked according to paper sizes. Specifically, as shownin FIG. 17, in case where the papers to be bound fit a predeterminedsize, a height M of the paper can be uniformly determined. Also, asalready mentioned, a lower end portion of an inner face of the fixedclamp 18 a, which is the reference position R, is always aligned with aforward side lateral edge of the sheet stack 100. Accordingly, adistance N from the reference position R to the forward side lateraledge 110 a of the cover 110 always matches the height M of the sheetstack, regardless of a thickness of the sheet stack to be bound. Inother words, regardless of a thickness of the sheet stack to be bound,the operator can uniformly determine with which position on the covertray 15 a forward side lateral edge 110 a of the cover 110 should bealigned. Consequently, a positioning mark to be used when using astandard sized cover can be definitely indicated on the cover tray 15,and resultantly the cover positioning can be easily performed whensetting the cover. Also, as already mentioned, in case of an oversizedcover that protrudes from the cover tray 15, the positioning scale 15 acan be drawn out to utilize the scales marked thereon for positioning.

Once the cover 110 has been set the switch on the operation panel 16 isturned on (step #18), and upon receipt of such signal the control unit76 activates the adhesive tank driving motor 78 to move the adhesivetank 23 (step #19).

Here, in case where the pad binding without a cover is selected as thebookbinding mode, since there is no need of setting a cover, theadhesive tank 23 is caused to move immediately after the start switch161 is turned on (step #14) and the pressing unit 4 has been lowered,without making a temporary stop.

Along with the travel of the adhesive tank 23, the adhesive is appliedto the back portion of the sheet stack 100 via the roller 24. Referringto a rotating direction of the roller, an amount of applied adhesivevaries depending on a thickness of the sheet stack, and in case wherethe sheet stack is thin an amount of the applied adhesive is prone to beinsufficient, which may result in a weak adhesion. Accordingly, in thisembodiment, a rotating direction of the roller 24 is controlled asfollows, according to the bookbinding mode selected. Here, a thicknessof the sheet stack is detected by the sheet stack thickness sensor 34(Ref. FIG. 7), to be distinguished whether thinner than a referencethickness.

Firstly, in case where the case binding is selected as a bookbindingmode, when a thickness of the sheet stack is thicker than a referencethickness (2.0 mm), a rotating direction of the roller is switched ineach of the forward and backward travel, and the rotating direction isforward with respect to the sheet stack in the travel of both ways.Specifically, in a forward travel in which the roller 24 moves in adirection indicated by the arrow 205, the roller is rotated in adirection of the arrow 220, and in a backward travel in which the roller24 moves in a direction of the arrows 206 and 207, the roller is rotatedin a direction of the arrow 221. In either case the rotating directionof the roller 24 is a forward direction with respect to a movingdirection thereof, i.e. a direction for sequentially applying theadhesive stuck to a surface of the roller 24 to the back of the sheetstack. Here, a timing for switching the rotating direction of the roller24 is controlled by a signal from the third adhesive tank positionsensor 31 c (Ref. FIG. 8).

Referring to FIG. 18A, when the detection piece 32 of the adhesive tankpasses the second adhesive tank position sensor 31 b on the way of abackward travel and such signal is input to the control unit 76, thecontrol unit 76 stops the rotation of the roller 24. Stopping in thisway the roller in the proximity of an end portion of the sheet stack 100prevents excessive application of the adhesive to a lateral end portionof the sheet stack 100, caused by scraping of the adhesive by suchportion of the sheet stack.

On the other hand, in case where the case binding is selected as abookbinding mode and the sheet stack is thinner than the referencethickness (2.0 mm), in a forward travel in which the roller 24 moves ina direction indicated by the arrow 205, the rotation of the roller isstopped, and in a backward travel in which the roller 24 moves in adirection of the arrows 206 and 207, the roller is rotated in adirection of the arrow 223, as shown in FIG. 18B. In the backwardtravel, the roller 24 is rotated in a reverse direction with respect tomoving direction thereof. In other words, in the forward travel theroller 24 rotates in such a direction that the adhesive stuck to asurface of the roller 24 is sequentially applied to the back of thesheet stack, and in the backward travel the roller 24 rotates in such adirection that the adhesive stuck to a surface of the roller is scrapedoff on to the back of the sheet stack. As a result, an increased amountof adhesive is applied in the backward travel, thereby increasing abonding strength.

In this case also, the rotation of the roller 24 is stopped halfway ofthe backward travel, to prevent excessive application of the adhesive toa lateral end portion of the sheet stack 100.

Meanwhile, the reference thickness of 2.0 mm adopted in this embodimenthas been established as a preferable range through the followingexperiments. Practically, a bookbinding apparatus according to thisembodiment was prepared, and papers and covers a thickness of 0.1 mmwere employed in various different thicknesses adjusted by varying anumber of sheets to be stacked, to which an adhesive was applied indifferent ways to examine a bookbinding performance. Decision on whetherthe adhesive is insufficient was made depending on whether the paper andthe cover fall apart when pulled, and the adhesive was regarded assufficient in case where either the cover or the paper was torn insteadof falling apart. Decision on whether the adhesive is excessive was madethrough a visual examination, in two levels of “excessive” and “ratherexcessive” among those which had a protrusion of the adhesive. Theresults are shown in Table 1. In Table 1, a circle stands for anexcellent finish of the book, a cross means defective finish, and atriangle represents insufficient adhesion, though apparently a bookshape was formed. Based on such experiment, a thickness of the sheetstack of 1.8 to 2.2 mm has been concluded to be a boundary region, and2.0 mm has been adopted as the reference thickness in this embodiment.Such a thickness range of the sheet stack may vary to a certain extentdepending on a nature of an adhesive to be used or an amount of anadhesive to be applied to the roller, however in case where a thicknessof most frequently used sheet stack is 25 mm or thinner, a desirableadhesive amount can be obtained in the foregoing range.

Specifically, since a relation as shown in FIG. 22 is observed betweenan amount of applied adhesive and a rotating direction of the roller, amore amount of adhesive can be applied by stopping the roller in aforward travel and reversely rotating on the way back, as long as athickness of the sheet stack is approx. 2 mm or thinner, than forwardlyrotating in both ways. Also, when the sheet stack is thin, an amount ofthe applied adhesive largely depend on a rotating direction of theroller, and forwardly rotating the roller in a forward travel butreversely rotating on the way back may result in excessive application,depending on an operational condition. Therefore, as long as the sheetstack is not thicker than approx. 2.0 mm, it is preferable to stop theroller in a forward travel and reversely rotate on the way back to thusprevent insufficient application of the adhesive, while in case wherethe sheet stack is thicker than 2.0 mm it is preferable to forwardlyrotate the roller in both ways. TABLE 1 Number of Sheet stack sheetsthickness Roller rotating direction Finish Amount of (pieces) (mm)Forward travel Backward travel grade adhesive 4 0.4 Forward Forward XInsufficient Stopped Reverse ◯ Appropriate 6 0.6 Forward Forward XInsufficient Stopped Reverse ◯ Appropriate 8 0.8 Forward Forward XInsufficient Stopped Reverse ◯ Appropriate 10 1.0 Forward Forward XInsufficient Stopped Reverse ◯ Appropriate 12 1.2 Forward Forward XInsufficient Stopped Reverse ◯ Appropriate 14 1.4 Forward Forward XInsufficient Stopped Reverse ◯ Appropriate 16 1.6 Forward Forward XInsufficient Stopped Reverse ◯ Appropriate 18 1.8 Forward Forward ΔRather insufficient Stopped Reverse ◯ Appropriate 20 2.0 Forward Forward◯ Appropriate Stopped Reverse ◯ Appropriate 22 2.2 Forward Forward ◯Appropriate Stopped Reverse Δ Rather insufficient 24 2.4 Forward Forward◯ Appropriate Stopped Reverse X Insufficient 26 2.6 Forward Forward ◯Appropriate Stopped Reverse X Insufficient 28 2.8 Forward Forward ◯Appropriate Stopped Reverse X Insufficient

On the other hand, in case where the pad binding is selected as abookbinding mode, it is preferable to forwardly rotate the roller 24 inboth ways along with the travel of the adhesive tank 23, irrespective ofa thickness of the sheet stack. In other words, the roller 24 rotates insuch a direction that the adhesive stuck to a surface of the roller 24is sequentially applied to the back of the sheet stack.

When the adhesive tank returns to the stand-by position at the foregoingstep and a signal from the adhesive tank position sensor 31 a has beenreceived, the control unit 76 drives the clamp motor 80 for verticalmovement to lift the pressing unit 4 until detected by the upper clampsensor 73, and then drives the movable plate driving motor 83 to movethe movable plate 46 toward the block bar 44, to thereby press the sheetstack 100 and the cover 110 (step #20).

Two components of the block bar 44 and the movable plate 46 are employedto press the sheet stack 100. At this stage the movable plate 46 isdriven by the movable plate driving motor 83, in which case, directlytransmitting a driving force of the motor to the movable plate 46 incursa problem that a pressing force varies depending on a thickness of thesheet stack 100. Accordingly, in this embodiment a driving mechanism ofthe movable plate 46 is constituted as follows.

A driving force of the movable plate driving motor 83 is transmitted tothe movable plate 46 via a pair of blocks 87 and 88 confronting eachother via a spring 85. To be more detailed, the first block 87 islocated on the side of the movable plate and the second block 88 islocated on the side of the movable plate driving motor 83, and aninterval between the blocks is adjustable via a supporting shaft 84penetrating through the both blocks. Since the supporting shaft 84 isinserted in the spring 85 for connecting the blocks, the blocks 87 and88 are urged in a direction to separate from each other. A flangeportion 84 a is formed on both end portions of the supporting shaft 84,for delimiting a maximum separation of the blocks 87 and 88. A clampstop sensor 75 constituted of a photointerrupter is located on the sideof the second block 88, and a detection piece 86 is disposed at aposition corresponding to the clamp stop sensor 75 on the side of thefirst block.

Accordingly, when the movable plate driving motor 83 is activated todrive the second block 88 toward the fixed plate 43, the first block 87moves together with the second block 88 because of an urging force ofthe spring 85. In this way, the movable plate is caused to move when themovable plate driving motor 83 is activated. Thereafter, once a forwardend portion of the movable plate 46 makes contact with the sheet stackor the block bar 44, the movable plate 46 is unable to proceed anyfarther; therefore a movement of the second block is absorbed in areduction of the interval between the blocks 87 and 88 produced by ashrink of the spring 85.

As shown in FIG. 19A, when the pressing unit 4 is lifted and the coverand the sheet stack make contact with each other, the adhesive 106applied to the back of the sheet stack 100 is pressed and squeezed outto a side not blocked by the block bar 44 (106 b of FIG. 19A). In thisstate, when the movable plate 46 moves toward the block bar, since themovable plate 46 is at a higher level than the fixed plate 43, the cover46 is folded upward, and the adhesive 106 b that has been squeezed outadheres to a lowermost portion along an inner lateral face of the sheetstack 100.

At this stage, even though an end portion of the movable plate 46 isbutted to the sheet stack 100, the movable plate driving motor 83 keepsdriving in a direction indicated by the arrow 207. In this case aninterval between the blocks 87 and 88 is gradually shortened, untilfinally the detection piece 86 meets the photointerrupter (clamp stopsensor 75). Upon receipt of such signal, the control unit 76 stopsdriving the movable plate driving motor 83. Such constitution permitspressing the sheet stack 100 with a uniform pressure regardless of athickness thereof.

When a predetermined time necessary for solidification of the adhesivehas elapsed with the sheet stack being pressed by the pressing unit 4,the control unit 76 releases the pressing unit 4 (FIG. 20A), and drivesthe clamp motor 80 for vertical movement so that the pressing unit 4 islowered as indicated by the arrow 230, until detected by the lower clampsensor 74 (FIG. 20B), and further drives the clamp motor 79 for forwardand backward movement to cause the pressing unit 4 to retreat asindicated by the arrow 231 (FIG. 20C, step #21). When the pressing unit4 has retreated, the shooter 45 is exposed right under the sheet stack.Inside the bookbinding apparatus, a slider 90 is installed close to aretreating position of the shooter 45; therefore when the lower frontdoor 13 under the front housing is opened up, a discharging path fromthe shooter 45 to outside the apparatus can be constituted as indicatedby the arrow 209 in FIG. 20A.

When the operating knob 14 is manipulated to release the clamp asindicated by the arrow 232 (FIG. 20D), a finished book 120 passesthrough the gap 45 a provided in front of the fixed plate 43 and fallsinto the shooter 45, to then slide down along the slider 90 and bedischarged out of the bookbinding apparatus 1.

As described throughout the foregoing passages, according to thebookbinding apparatus of this embodiment, the adhesive tank 23 is heatedonly at the stand-by position and a non-contact induction heater whichoffers a high thermal efficiency is employed for heating; therefore asystem in which the adhesive tank moves can be adopted. As a result, theadhesive tank 23 can be designed in small dimensions, and a start-uptime can be shortened, and also smell of the adhesive that volatilizesfrom the adhesive tank can be reduced.

Also, since the adhesive tank 23 is constituted of a main body of anon-ferromagnetic material and a heating plate, the main body of theadhesive tank is not directly heated; therefore overheating of theadhesive at a contact area of the adhesive and the adhesive tank, andhence scorching of the adhesive can be prevented. Further, since theroller is also constituted of a non-ferromagnetic material, the adhesivecan be prevented from being overheated on a surface of the roller.

Also, since the adhesive tank is provided with an inner bottom faceinclined toward a position where the roller is installed, the adhesivegathers close to the roller even though the adhesive in the adhesivetank has been consumed, and therefore the roller can be sufficientlydipped in the adhesive even when a surface level of the adhesive hasdropped.

Also, according to the bookbinding apparatus of this embodiment, sincean appropriate amount of adhesive pellets are automatically supplied bythe adhesive supply unit, when a decrease of the adhesive in theadhesive tank due to consumption has been detected, shortage of theadhesive is not incurred in the adhesive tank despite constituting theadhesive tank in small dimensions for the purpose of moving the adhesivetank. Further, an adhesive of a pellet form is used in the adhesivesupply unit so that the adhesive pellets can roll down through aninclined duct, and besides a predetermined amount of adhesive pellets isautomatically supplied each time through an arrangement with twopartition plates. Therefore, a transport mechanism for the adhesive andan adhesive measuring mechanism are not required, and accordingly thebookbinding apparatus can be constituted in a compact size. Also, sincethe adhesive supply unit is installed at an opposite position across thesheet stack to the stand-by position, which is also a heating positionof the adhesive tank, i.e. at a separate position from the heat sourceof the adhesive tank, the adhesive stored in the adhesive supply unitdoes not melt owing to the heat from the hearing device of the adhesivetank, and besides a problem of the smell diffusing from the adhesive canbe eliminated.

Further, according to the bookbinding apparatus of this embodiment, inview of the new findings that an amount of applied adhesive variesdepending on a moving direction and a rotating direction of the roller,operation of the roller is constituted such that a rotating direction isswitched in each of the forward and backward travel, i.e. the roller isstopped in a forward travel, but is reversely rotated against a sheetstack with respect to its moving direction on its way back so that theadhesive is scraped off by the back of the sheet stack and resultantlyan increased amount of adhesive is applied to the sheet stack, in casewhere the sheet stack is thinner than a predetermined referencethickness (2.0 mm). On the other hand, in case where the sheet stack isthicker than the reference thickness, the roller is rotated in a forwarddirection in both of the forward and backward travels, in order toincrease an amount of applied adhesive.

Further, at a final edge the sheet stack, the roller is stopped in theproximity of the final end portion of the sheet stack in order toprevent the adhesive from being scraped off by the final edge so that anexcessive amount of adhesive is not stuck to the end portion of thesheet stack. In this way, since a portion of adhesive remaining on asurface of the roller is spread over the sheet stack, and therefore theexcessive application of the adhesive can be prevented.

The present invention is not limited to the foregoing embodiment, but ispracticable in various other aspects.

Also, an appropriate combination of any of the components orconstitutions in the foregoing embodiment can also provide an effectduly expected from those components or constitutions.

Although the present invention has been fully described in connectionwith the preferred embodiments thereof with reference to theaccompanying drawings, it is to be noted that various changes andmodifications are apparent to those skilled in the art. Such changes andmodifications are to be understood as included within the scope of thepresent invention as defined by the appended claims unless they departtherefrom.

INDUSTRIAL APPLICABILITY

According to the bookbinding apparatus of the present invention, sincethe adhesive tank is contactlessly heated in a stand-by state, theadhesive tank can easily be constituted to be movable, and because ofconstituting such that the adhesive tank moves in an adhesiveapplication process, the bookbinding apparatus can be constituted in asmall width and also a capacity of the adhesive tank can be madesmaller, thereby reducing a smell of the adhesive diffusing from theadhesive tank. Consequently, the bookbinding apparatus according to thepresent invention is appropriate as a compact and simple bookbindingapparatus to be used in an office, school, home, etc.

1. A bookbinding apparatus comprising: a movable adhesive tank forretaining therein an adhesive melted by heat; a roller rotatablysupported with the tank so as to dip a lower portion thereof in theretained in the adhesive tank, for applying the to a sheet stack along alateral edge thereof; a holding unit capable of holding the sheet stack;an adhesive tank carrier for disposing the adhesive tank and the rollerat a stand-by position located outside a longitudinal end face of thesheet stack held by the holding unit in a stand-by stage, and moving theadhesive tank and the roller together from the stand-by position in alongitudinal direction of the sheet stack substantially through anentire area under a back face thereof in a bookbinding stage; and anon-contact heater for contactlessly heating the adhesive tank disposedat the stand-by position to melt the adhesive.
 2. The bookbindingapparatus according to claim 1, wherein the non-contact heater isprovided with an electromagnetic induction heating coil; and theadhesive tank is constituted of a material containing a ferromagneticmaterial.
 3. The bookbinding apparatus according to claim 2, wherein thenon-contact heater is immovably placed at a stand-by position.
 4. Thebookbinding apparatus according to claim 3, wherein the adhesive tank isprovided with a container-shaped main body of a non-ferromagneticmaterial for retaining therein the adhesive and a ferromagnetic heatingportion located on an outer surface of the main body; and thenon-contact heater is located so as to confront the heating portion ofthe adhesive tank placed at the stand-by position.
 5. The bookbindingapparatus according to claim 1, wherein the roller is constituted of anon-ferromagnetic material.
 6. The bookbinding apparatus according toclaim 1, wherein the adhesive tank is provided with an inclined bottomwall in an adhesive retaining region of a container-shaped main body ofthe adhesive tank to retain the adhesive therein, for providing a deeperportion corresponding to a position of the roller.
 7. The bookbindingapparatus according to claim 1, wherein the adhesive tank is providedwith a fin for promoting melting of the adhesive, erected on a bottomwall in the adhesive retaining region of the container-shaped main bodyof the adhesive tank to retain the adhesive therein.
 8. The bookbindingapparatus according to claim 1, further comprising: an adhesive supplyunit installed opposite to the stand-by position of the adhesive tankacross the sheet stack, including a storing section for storing thereinadhesive pellets to be transformed into the melted adhesive retained inthe adhesive tank, a pellet supply path downwardly extending from abottom portion of the storing section, and a pellet outlet through whichthe adhesive pellets transferred through the pellet supply path aredischarged; and an adhesive supply control unit for controlling asupplying timing of the adhesive pellets from the adhesive supply unit,such that a predetermined amount of adhesive pellets is discharged fromthe pellet outlet to the adhesive tank at a time that the adhesive tankhas reached a position where the adhesive tank can receive the adhesivepellets discharged from the pellet outlet, thereby the adhesive pelletssupplied into the adhesive tank are melted.
 9. The bookbinding apparatusaccording to claim 8, further comprising: a level detection unit fordetecting a surface level of the adhesive retained in the adhesive tank;wherein the adhesive supply control unit supplies the adhesive pelletsuntil the adhesive surface exceeds a reference level, when the adhesivesurface level has been detected to be lower than the reference level bythe level detection unit.
 10. The bookbinding apparatus according toclaim 8, further comprising: two openable partition plates disposedinside the supply path with a predetermined interval therebetween, sothat a predetermined amount of adhesive pellets are stored between thepartition plates; wherein the adhesive supply control unit open or closethe two partition plates independently.
 11. The bookbinding apparatusaccording to claim 10, wherein each of the two partition plates is of adisk shape with an opening, and are fixed by a shaft disposedsubstantially parallel to the supply path such that a rotation phase ofthe opening of the respective partition plates is different from eachother; and the adhesive supply control unit drives the shaft to rotatesuch that only one of the partition plates permits a communicationthrough the supply path.
 12. An adhesive pellet of a substantiallyspherical shape, to be used with the adhesive supply unit usable withthe bookbinding apparatus according to claim
 8. 13. The bookbindingapparatus according to claim 1, further comprising: a binding modeselection unit for selecting a bookbinding mode according to a signalidentifying whether a case binding mode of binding a sheet stack with acover or a pad binding mode of binding a paper pad without a cover; anda rotation control unit for switching a roller controlling modeaccording to the bookbinding mode selected by the bookbinding modeselection unit.
 14. The bookbinding apparatus according to claim 13,wherein the adhesive tank carrier serves to move the adhesive tank andthe roller back and forth in a longitudinal direction of the sheetstack; and the rotation control unit rotates the roller in a forwarddirection with respect to a moving direction thereof, during both of theforward and backward travels of the adhesive tank, when a pad bindingmode in which a cover is not provided to the sheet stack is selected bythe bookbinding mode selection unit.
 15. The bookbinding apparatusaccording to claim 13, wherein the adhesive tank carrier serves to movethe adhesive tank and the roller back and forth in a longitudinaldirection of the sheet stack; and the rotation control unit rotates theroller in a different direction according to a moving direction thereof.16. The bookbinding apparatus according to claim 15, further comprising:a thickness detecting device for detecting a thickness of the sheetstack held by the holding unit; wherein the rotation control unit stopsa rotation of the roller during a forward travel of the adhesive tankbut rotates the roller in a reverse direction with respect to the movingdirection during a backward travel of the adhesive tank when a thicknessof the sheet stack has been detected to be equal to or thinner than areference thickness, while the rotation control unit rotates the rollerin a forward direction with respect to a moving direction thereof duringboth of the forward and backward travels of the adhesive tank, when athickness of the sheet stack has been detected to be thicker than thereference thickness, in case where the case binding mode of providing acover to the sheet stack is selected by the bookbinding mode selectionunit.
 17. The bookbinding apparatus according to claim 16, wherein thereference thickness is in a range of 1.8 to 2.2 mm.
 18. The bookbindingapparatus according to claim 16, further comprising: a positiondetection unit for detecting a position of the adhesive tank; wherein,once the adhesive tank reaches a predetermined position during abackward travel of the adhesive tank, the rotation control unit stopsthe rotation of the roller during the subsequent travel of the adhesivetank from the predetermined position to a final edge of the sheet stack